KeysOfType

KeysOfType<T, V> = { [K in keyof T]: T[K] extends V ? K : never }[keyof T]

Source: common.ts:232

Extracts keys of T that have values assignable to V

Type Parameters

T — Object type
V — Value type to match

Example

CODE

interface User {
  id: number
  name: string
  email: string
  age: number
}

type StringKeys = KeysOfType<User, string> // 'name' | 'email'
type NumberKeys = KeysOfType<User, number> // 'id' | 'age'